KR20170120721A - Copolymerizable (meth)acrylic acid polymer, optical alignment film and phase difference film - Google Patents

Abstract

(Meth) acrylic acid polymer having excellent properties such as high solubility in a solvent having low toxicity and low environmental load, a composition for a photo alignment layer comprising the same, a photo alignment layer And a phase difference film in which a liquid crystal compound is oriented on the photo alignment film.
The copolymerizable (meth) acrylic acid polymer has a repeating unit represented by the general formula (I) (each symbol is as defined in the specification).

Description

(Meth) acrylic acid polymer, a photo alignment film, and a phase difference film (Copolymerizable (meth) acrylic acid polymer, optical alignment film and phase difference film)

The present invention relates to a copolymerizable (meth) acrylic acid polymer, a photoalignment film and a retardation film, and more particularly to a copolymerizable (meth) acrylic acid polymer having a side chain having a carboxyl group at the terminal and a side chain having an acrylate ester moiety at the terminal , A composition for a photo alignment layer comprising the same, a photo alignment layer having a liquid crystal aligning property in a film made of the composition, and a retardation film having a liquid crystal compound oriented on the photo alignment layer.

In recent years, a retardation film (optically anisotropic film) has been used in various forms in the field of displays (including liquid crystal displays and flexible displays). Such a retardation film is produced by applying a liquid crystalline compound onto a film (or a substrate) having liquid crystal aligning ability, but conventionally, a method of imparting liquid crystal aligning ability to the film (or substrate) Is known. As such a method, for example, a rubbing process in which a polymer resin film such as polyimide coated on the surface of a substrate is rubbed in a single direction or the like is known, and is used for forming an alignment film for a liquid crystal display device and the like. However, in such a method, contamination of the liquid crystal manufacturing line due to the generation of fine dust and destruction of the TFT (thin film transistor) element due to static electricity cause a decrease in the product ratio in the manufacturing process of the liquid crystal panel There is a problem that quantitative orientation control is difficult.

Therefore, various photo alignment films for imparting liquid crystal aligning ability by light irradiation have been proposed in place of the rubbing treatment (Patent Documents 1 to 3). Particularly, in Patent Document 2, a photo-alignment material obtained by polymerizing a monomer having a carboxyl group at the photoreactive side chain terminal end is described as exhibiting a good photoreaction efficiency. However, such a photo alignment material has a problem that it is difficult to suppress the production cost because the monomers used as raw materials are expensive. Further, Patent Document 3 describes a copolymer synthetic polymer which solves the above problems by converting a part of the monomer into another monomer having lower cost. Such other monomers have a carboxyl group at the terminal but they do not contain a structure showing photoreactivity.

Generally, in order to produce a phase difference film using such a polymer, a polymer is first dissolved in a solvent, the solution is coated on a substrate, dried, irradiated with linearly polarized light or the like, . Then, a liquid crystal compound is coated on the photo alignment layer, the liquid crystalline compound is heated to orient the liquid crystalline compound, and after UV curing, the alignment property is improved by heating to obtain a phase difference film. In such a process, it is preferable that the solvent for dissolving the polymer for the first time is as low in toxicity and environmental load as possible. However, the polymers described in Patent Document 2 and Patent Document 3 have poor solubility and use solvents having relatively high toxicity and environmental load There was a problem that it can not be done.

The amount of exposure when linearly polarized light is irradiated onto the polymer coated on the substrate is in a range that is optimal for producing the photo alignment film (the optimum polarized light exposure amount, which is simply referred to as the optimum exposure amount in this specification) There is also a limit value (limit polarized light exposure amount, in this specification, simply referred to as the limit exposure amount) in which the film deteriorates when the exposure amount is exceeded. Therefore, in order to manufacture a highly suitable photo alignment film, it is necessary to adjust the exposure amount surely. Such adjustment is performed by adjusting the exposure intensity and the exposure time by a machine that irradiates the polarized light. However, if the value of the optimum exposure amount is small (light sensitivity is high) and the difference from the limit exposure amount is small, It is very difficult to carry out the process.

When a retardation film is produced by orienting a liquid crystalline compound in a photo alignment layer, it is necessary to heat the liquid crystalline compound to a high temperature exceeding 200 캜 after UV curing. However, before and after the heating process, (Heat resistance is low).

(Patent Document 1) JPH08-015681 (Patent Document 2) JP2007-304215 (Patent Document 3) JP2008-276149

In the above background, the present invention provides a composition for a photo-alignment film comprising a copolymer (meth) acrylic acid polymer capable of dissolving in a solvent having a low toxicity and an environmental load, a composition comprising the composition, And a phase difference film in which a liquid crystal compound is oriented on the photo alignment film.

(Meth) acrylic acid polymer capable of suppressing a decrease in birefringence (having a high heat resistance) in a film formation process of a liquid crystal film, that is, a film heating (firing) process, a composition for a photo alignment film comprising the same , A photo alignment layer having a liquid crystal aligning property in a film made of the composition, and a retardation film in which a liquid crystal compound is oriented on the photo alignment layer.

It is another object of the present invention to provide a method for producing a photo alignment film which is capable of producing a photo alignment film having a relatively large value of the amount of polarized light to be irradiated (light sensitivity is low) and / or a large difference between the optimum exposure amount and the limit exposure amount, (Meth) acrylic acid polymer, a composition for a photo alignment layer comprising the same, a photo alignment layer generating a liquid crystal aligning function in a film made of the composition, and a retardation film in which a liquid crystal compound is oriented on the photo alignment layer .

As a result of intensive studies, the present inventors have found that when a novel copolymerizable (meth) acrylic acid polymer having both a side chain having a carboxyl group at the terminal thereof and a side chain having an aryl acrylate ester (preferably cinnamate ester) And the present invention has been accomplished.

That is,

〔One〕

The compound of formula (I)

Wherein R ¹ is a hydrogen atom or a methyl group, R ² is an alkyl group, or a phenyl group substituted with a group selected from an alkyl group, an alkoxy group, a cyano group and a halogen atom, and the ring A and the ring B are each independently,

[Wherein each of X ^{1 to} X ³⁸ independently represents a hydrogen atom, an alkyl group, an alkoxy group, a halogen atom or a cyano group]

Z is a group represented by -CH = CHCOO- (trans) or -N = N-, p and q are each independently any one of 1 to 12, m and n are , 0.65? M? 0.95, 0.05? N? 0.35, and m + n = 1 in the copolymer.

(Meth) acrylic acid polymer having a repeating unit represented by the following formula

[2] In another aspect, the present invention provides a compound represented by formula (I-A)

Wherein R ¹ is a hydrogen atom or a methyl group and R ² is an alkyl group or a phenyl group substituted with a group selected from the group consisting of an alkyl group, an alkoxy group, a cyano group and a halogen atom, each of X ^{1A to} X ^4A , A hydrogen atom, an alkyl group, an alkoxy group, a halogen atom or a cyano group, and the ring B is

[Note that X ^{1B to} X ^4B And each of X ^{31B to} X ^38B independently represents a hydrogen atom, an alkyl group, an alkoxy group, a halogen atom or a cyano group.

And Z is a group represented by -CH = CHCOO- (trans) or -N = N-, p and q are each independently any integer of 1 to 12, and m and n are, 0.65? M? 0.95, 0.05? N? 0.35, and m + n = 1.

(Meth) acrylic acid polymer having a repeating unit represented by the following formula

[3] The present invention also relates to a compound represented by the general formula (I-a)

Wherein R ¹ is a hydrogen atom or a methyl group, R ² is an alkyl group, or a phenyl group substituted with a group selected from an alkyl group, an alkoxy group, a cyano group and a halogen atom, each of X ^{1A to} X ^4A independently represents a hydrogen An atom, an alkyl group, an alkoxy group, a halogen atom or a cyano group,

[Wherein each of X ^{1B to} X ^4B and X ^{31B to} X ^38B independently represents a hydrogen atom, an alkyl group, an alkoxy group, a halogen atom or a cyano group]

P and q are each independently any one of integers from 1 to 12, and m and n satisfy a relationship of 0.65? M? 0.95, 0.05? N? 0.35, and m + n = Is the mole fraction of each monomer in the polymer.

(Meth) acrylic acid polymer having a repeating unit represented by the following formula

[4] The present invention also relates to a compound represented by the general formula (I-b)

Wherein R ¹ is a hydrogen atom or a methyl group and R ² is an alkyl group or a phenyl group substituted with a group selected from an alkyl group, an alkoxy group, a cyano group and a halogen atom, and X ^{1 to} X ^{4 A} and X 3 ^{1B to} X ^38B P and q are each independently an integer of 1 to 12, and m and n are each independently in the range of 0.65? M? 0.95, 0.05? N? 0.35, and m + n = 1).

(Meth) acrylic acid polymer having a repeating unit represented by the following formula

[5] In addition, the present invention relates to a compound represented by formula (Ic)

Wherein R ¹ is a hydrogen atom or a methyl group, R ² is an alkyl group, or a phenyl group substituted with a group selected from an alkyl group, an alkoxy group, a cyano group and a halogen atom, and X ^{1 to} X ^{4 A} and X ^{1B to} X ^4B Each independently represent a hydrogen atom, an alkyl group, an alkoxy group, a halogen atom or a cyano group, Z is a group represented by -CH = CHCOO- (trans) or -N = N-, p and q are each independently M and n are molar fractions of respective monomers occupying in the copolymer satisfying the relationship of 0.65? M? 0.95, 0.05? N? 0.35, and m + n = 1 (Meth) acrylic acid polymer having units,

[6] A composition for a photo alignment film comprising the copolymerizable (meth) acrylic acid polymer according to any one of [1] to [5]

[7] A photo-alignment film in which light having anisotropy is irradiated to a film made of the composition for photo-alignment film of the above-mentioned [6]

[8] A retardation film in which a liquid crystal compound is oriented on the photo alignment film of [7].

The copolymer (meth) acrylic acid polymer (I) of the present invention has excellent characteristics of solubility in methyl ethyl ketone and / or cyclohexanone and / or 1-methoxy-2-propanol which are low toxic and low in environmental load Respectively. Since methyl ethyl ketone, cyclohexanone and 1-methoxy-2-propanol have low boiling points of about 80 ° C and about 155 ° C and about 120 ° C, respectively, the drying process for removing the solvent is facilitated .

Further, when the polymer of the present invention is used as an orientation film and the retardation film is produced by orienting the liquid crystalline compound again, it is possible to suppress a decrease in the birefringence of the film in the heating step in the film formation process of the retardation film (that is, (I.e., the heat resistance of the film becomes high) and / or the value of the optimum exposure amount of the polarized light irradiated when the photo alignment film is produced becomes relatively large and / or the difference between the optimum exposure amount and the limit exposure amount becomes large .

In the polymer (1) of the present invention, preferred specific examples are shown below.

The compound of formula (I-A)

[Wherein the symbols have the same meanings as above]

(Meth) acrylic acid polymer having a repeating unit represented by the following formula (1).

In general formula (IB)

Wherein R ¹ is a hydrogen atom or a methyl group, R ² is an alkyl group, or a phenyl group substituted with a group selected from an alkyl group, an alkoxy group, a cyano group and a halogen atom, the ring A and the ring B are each independently

[Wherein each of X ^{1 to} X ³⁸ independently represents a hydrogen atom, an alkyl group, an alkoxy group, a halogen atom or a cyano group]

P and q are each independently any one of integers from 1 to 12, and m and n satisfy a relationship of 0.65? M? 0.95, 0.05? N? 0.35, and m + n = Is the mole fraction of each monomer in the polymer.

(Meth) acrylic acid polymer having a repeating unit represented by the following formula (1).

In general formula (I-a)

[Wherein the symbols have the same meanings as defined above]

(Meth) acrylic acid polymer having a repeating unit represented by the following formula (1).

In general formula (I-b)

[Wherein the symbols have the same meanings as defined above]

(Meth) acrylic acid polymer having a repeating unit represented by the following formula (1).

(I-c) < / RTI >

[Wherein the symbols have the same meanings as defined above]

In the general formula (I) (including the formulas (IA) and (IB) and the formulas (Ia) to (Ic)) of the present invention, as the R ¹ , a methyl group is preferable. R ² is preferably an alkyl group or a phenyl group substituted with a group selected from an alkyl group, an alkoxy group, a cyano group and a halogen atom, more preferably an alkyl group or a phenyl group substituted with a cyano group, Do. Another preferable example of R ² is an alkyl group, or a phenyl group substituted with an alkoxy group or a cyano group, and among these, a phenyl group substituted with an alkyl group or an alkoxy group is preferable. Other preferred examples of R ² include a phenyl group substituted with an alkoxy group or a cyano group, and a phenyl group substituted with an alkoxy group is more preferable. Another preferred example of R ² is an alkyl group. Each of X ^{1 to} X ³⁸ is preferably a hydrogen atom or a halogen atom. p and q are all preferably an integer of 3 to 9, preferably an integer of 5 to 7, and most preferably 6. m, preferably about 0.75 m < = about 0.85, and most preferably about 0.8. The preferable range of the corresponding n is a range determined by itself from m + n = 1. That is, preferably in the range of about 0.15? N? About 0.25, and most preferably about 0.2.

In the general formula (I) of the present invention, X ^{1A to} X ^4A are preferably a hydrogen atom or a halogen atom, particularly preferably any one of X ^{1A to} X ^4A is a halogen atom and the others are hydrogen atoms, And most preferably all hydrogen atoms. X ^{31B to} X ^38B are preferably a hydrogen atom or a halogen atom, and most preferably all of them are hydrogen atoms.

As the alkyl group of R ² or the alkyl group of the substituent of the phenyl group of R ^2, an alkyl group of 1 to 12 carbon atoms can be exemplified, and among them, those having 1 to 6 carbon atoms are more preferable, and those having 1 to 4 carbon atoms are most preferable Include methyl group. As the alkoxy group of the substituent of the phenyl group of R ² , an alkoxy group having 1 to 12 carbon atoms can be enumerated. Of these, an alkoxy group having 1 to 6 carbon atoms, more preferably 1 to 4 carbon atoms, Time. As the halogen atom of the substituent of the phenyl group of R ² , a fluorine atom, a chlorine atom, a bromine atom and an iodine atom can be mentioned. Of these, a fluorine atom is preferable. As X ^{1 to} X ³⁸ , examples of the alkyl group include those having 1 to 4 carbon atoms, of which a methyl group is most preferable, and an alkoxy group having 1 to 4 carbon atoms is exemplified, among which a methoxy group is most preferable , And examples of the halogen atom include a fluorine atom, a chlorine atom, a bromine atom and an iodine atom, of which a fluorine atom is preferable.

In the present specification, X ^1A to X ^38A represent the case where X ¹ to X ³⁸ , which are substituents on the ring A or ring B, are substituents on the ring A, and X ^{1B to} X ^38B are substituents on the ring B . Accordingly, the description of the X ¹ ~X ³⁸ is that can be applied to, as X ^1A and X ^1B ~X ~X ^{38A 38B.}

The polymer (I) of the present invention is a polymer (I)

[Wherein the symbols have the same meanings as defined above]

(M1) represented by the general formula (III), and the amount of the (meth) acrylic acid monomer

[Wherein the symbols have the same meanings as defined above]

(Meth) acrylic acid monomer (M2) represented by the following general formula (1) in a solvent-free or solvent-free manner. Polymerization can be carried out using light or heat. In the polymerization step, the method of putting the material or the solvent is not particularly limited, and the polymerization may be started after all the materials are put into the reaction vessel before the polymerization. After mixing M1 and M2, After the polymerization is started for a part, the remainder may be added step by step by dropwise addition or partial introduction.

Other monomers may also be contained in the polymerization of M1 and M2, although this is not essential. As long as such a monomer is a compound having a polymerizable ethylenically unsaturated bond, the monomer is not particularly limited in any other respects, You do not have to have sex.

Examples of the monomer include methyl (meth) acrylate, t-butyl (meth) acrylate, stearyl (meth) acrylate, cyclohexyl (meth) acrylate, ethoxyethyl (Meth) acrylic monomers such as hydroxyethyl (meth) acrylate, phenyl (meth) acrylate and N, N-dimethylacrylamide, styrene,? -Methylstyrene, p- styrenesulfonic acid, Vinyl monomers such as vinylimidazole, vinyl acetate, vinylpyridine, 2-vinylnaphthalene, vinyl chloride, vinyl fluoride, N-vinylcarbazole, vinylamine, vinylphenol and N- Aryl-1,2-dimethoxybenzene, 4-arylphenol, and 4-methoxyarylbenzene; and maleimides such as phenylmaleimide and cyclohexylmaleimide.

When polymerization is carried out in a solution, a general-purpose organic solvent can be used without particular limitation. Specific examples of the solvent include alcohols such as ethanol, propanol and butanol, ketone solvents such as acetone, methyl ethyl ketone, methyl isobutyl ketone, cyclohexanone and cyclopentanone, ethyl acetate, butyl acetate, propylene glycol mono Ether solvents such as diethyl ether and diglyme; hydrocarbon solvents such as hexane, cyclohexane, methylcyclohexane, toluene and xylene; nitrile solvents such as acetonitrile; , Amide solvents such as N-methylpyrrolidone and dimethylacetamide, and the like. These solvents may be used singly or in combination of two or more kinds.

In the above polymerization, a polymerization initiator can be used. Specific examples of the polymerization initiator include azobisisobutyronitrile (AIBN), diethyl-2,2'-azobisisobutylate (V-601), 2,2'-azobis (2,4-dimethylvaleronitrile) and dimethyl azobismethylpropionate; peroxide-based polymerization initiators such as benzoyl peroxide, hydrogen peroxide and lauroyl peroxide; peroxides such as potassium persulfate and ammonium persulfate; And a persulfate-based polymerization initiator. Any of these polymerization initiators may be used alone, or two or more of them may be used in combination.

The temperature at the time of polymerization varies depending on the kinds of the monomers M1 and M2, the kind of the polymerization solvent, the initiator species and the like, but is preferably in the range of 40 to 150 占 폚, more preferably 50 to 120 占 폚.

The polymer (1) of the present invention thus obtained can be used as a composition for a photo alignment layer by appropriately adding a component usually contained in a polymerizable composition that generates polymerization by light and heat in addition to a photopolymerization initiator, a surfactant, and a solvent have. The content of these optional components is not particularly limited, but usually about 1 to about 10% by weight of a photopolymerization initiator, about 0.1 to about 5% by weight of a surfactant, about 70 to about 5% by weight of a solvent 99% by weight.

As a photopolymerization initiator, any of commonly used general photopolymerization agents may be used for forming a uniform film by a small amount of light irradiation. Specific examples thereof include azonitrile-based photopolymerization initiators such as 2,2'-azobisisobutyronitrile and 2,2'-azobis (2,4-dimethylvaleronitrile), Irgacure 907 Aminoketone type photopolymerization initiator such as Irgacure 369 (manufactured by Specialty Chemicals Inc.), 4-phenoxydichloroacetophenone, 4-t-butyldichloroacetophenone, diethoxy 1-hydroxycyclohexyl phenyl ketone, 2-benzyl-2-dimethylamino-1- (4-fluorophenyl) Based photopolymerization initiators such as benzophenone, benzoin methyl ether, benzoin ethyl ether, benzoin isopropyl ether and benzyl dimethyl ketal, benzophenone-based photopolymerization initiators such as benzophenone , Benzoyl benzoic acid, methyl benzoyl benzoate, 4-phenyl benzophenone, hydroxybenzophenone, acrylated benz Benzophenone-based photopolymerization initiators such as 4-benzoyl-4'-methyldiphenyl sulfide, 2-chlorothioxanthone, 2-methylthioxanthone, isopropylthioxanthone, 2,4-diisopropylthio 2-phenyl-4,6-bis (trichloromethyl) -s-triazine, 2- (p-methoxyphenyl) (Trichloromethyl) -s-triazine, 2- (p-methoxyphenyl) -4,6-bis (trichloromethyl) (Trichloromethyl) -s-triazine, 2,4-bis (trichloromethyl) -6-styryl s-triazine, 2- (naphtho-1-yl) -4 (Trichloromethyl) -s-triazine, 2- (4-methoxynaphtho-1-yl) -4,6-bis Triazine type photopolymerization initiators such as trichloromethyl- (piperonyl) -6-triazine and 2,4-trichloromethyl (4'-methoxystyryl) -6-triazine, carbazole-based photopolymerization initiators, Azole Succinic anhydride, succinic anhydride, succinic acid, succinic acid, succinic acid, succinic acid, succinic acid, succinic acid, succinic acid, And a photopolymerization initiator such as tetraphenone, 3,3 ', 4,4'-tetra (t-butylperoxycarbonyl) benzophenone, 4,4'-diethylaminobenzophenone and thioxanthone. As the photopolymerization initiator, either one may be used alone, or two or more photopolymerization initiators may be used together.

As the surfactant, any surfactant generally used for forming a uniform film can be used. Specific examples thereof include sodium lauryl sulfate, ammonium lauryl sulfate, triethanolamine lauryl sulfate, polyoxyethylene alkyl ether sulfate, alkyl ether phosphate, sodium oleyl succinate, potassium myristate, potassium cocoyl fatty acid, sodium Nonionic surface active agents such as polyethylene glycol monolaurate, sorbitan stearate, glyceryl myristate, glyceryl dioleate, sorbitan stearate, sorbitan oleate, and the like; A cationic surfactant such as stearyltrimethylammonium chloride, behenyltrimethylammonium chloride, stearyldimethylbenzylammonium chloride, and cetyltrimethylammonium chloride; a cationic surfactant such as laurylbetaine, alkylsulfobetaine, cocamidopropylbetaine, alkyldimethyl Alkyl betaines such as betaine amino acetate, alkyl imidazolines, lauroyl sarcosine (Such as BYK-361, BYK-306, BYK-307 (manufactured by Big Chemical Japan), Fluoride FC430 (manufactured by Sumitomo 3M), Megafac F171 and R08 Manufactured by Nippon Ink Kagaku Kogyo Co., Ltd.) and the like. Any of these surfactants may be used alone, or two or more surfactants may be used in combination.

Examples of the solvent include toluene, ethylbenzene, ethylene glycol monomethyl ether, ethylene glycol dimethyl ether, propylene glycol methyl ether, dibutyl ether, acetone, methyl ethyl ketone, ethanol, propanol, cyclohexane, cyclopentanone, methylcyclohexane, tetra There may be mentioned, for example, hydrofuran, dioxane, cyclohexanone, n-hexane, ethyl acetate, butyl acetate, propylene glycol methyl ether acetate, methoxybutyl acetate, N-methylpyrrolidone, dimethylacetamide, Methyl ethyl ketone and cyclohexanone are preferable from the viewpoints of toxicity and environmental load and / or from the viewpoint of content dissolution to a resin substrate (for example, polyethylene terephthalate (PET), cycloolefin polymer (COP), etc.). Either one of them may be used alone, or two or more of them may be used in combination. In particular, the polymer (I) of the present invention has excellent characteristics that it is also soluble in methyl ethyl ketone, cyclohexanone, and 1-methoxy-2-propanol.

By applying the thus obtained composition for photo-alignment film of the present invention onto a substrate to remove the solvent to form a film, irradiating the film with light having anisotropy, and heating the film to again cause the liquid crystal alignment capability, An alignment film can be formed.

As a method of applying the composition for a photo alignment layer, any method generally known in the field may be used, and examples thereof include a spin coating method, a bar coating method, a die coating method, a screen printing method and a spray coating method. After application of the composition, it is dried to remove the solvent to form a layer of the composition. The drying step may be any method commonly used in this field, and the resin layer is immobilized in a fixed form until the film is formed.

Examples of usable substrates include glass substrates such as alkali glass and alkali-free glass, glass substrates such as polyimide, polyamide, acrylic resin, polyvinyl alcohol, triacetylcellulose, polyethylene terephthalate, cycloolefin polymer, polyethylene, polycarbonate , Resin materials such as polystyrene and polytetrafluoroethylene, and metal materials such as iron, aluminum and copper, and glass substrates are more preferable.

Examples of the light having anisotropy include, for example, partial polarization other than linearly polarized light. Here, the term "linearly polarized light" refers to light whose plane including the oscillation direction of an electric field (or magnetic field) is one specific, and partial polarized light means that the intensity of vibration of an electric field (or magnetic field) is stronger than the other direction with respect to a specific direction. The linearly polarized light can be solidified by using a polarizing filter or a polarization prism for the light from the light source. The partial polarization is obtained by using a partial polarization filter. In the present invention, any light having anisotropy can be used, but it is preferable to use linearly polarized light for efficient optical alignment. The light to be irradiated is not particularly limited as long as it is an irradiation line that generates a chemical reaction by irradiation such as infrared rays, visible rays, ultraviolet rays (near ultraviolet rays, far ultraviolet rays), X rays, charged particle rays In general, however, the radiation is often in the range of 200 nm to 500 nm, and near-ultraviolet light of 350 nm to 450 nm is preferable in terms of effectively generating the optical crosslinking. Examples of the light source include a xenon lamp, a high-pressure mercury lamp, a high-pressure mercury lamp, and a metal halide lamp. The wavelength range to be irradiated may be limited by using an interference filter, a color filter, or the like for purple external light or visible light obtained from such a light source. The irradiation energy (optimum exposure dose) varies depending on the kind of the polymer (I), but is usually about 5 mJ / cm 2 to 50 mJ / cm 2.

When a photomask is used to irradiate the polarized light, two or more of the photomasks may have a liquid crystal alignment function in a pattern in a different direction. Specifically, a composition for a photo alignment layer of the present invention is coated and dried, a photomask is placed thereon, and light having anisotropy is irradiated thereto to give liquid crystal aligning ability only to the exposed portion. If necessary, the orientation is changed, By repeating this, the liquid crystal alignment ability can be generated in a pattern shape in a plurality of directions.

When the heating is performed after the light irradiation, the heating polymerization progresses and a photo-alignment film having higher durability against light, heat, etc. can be obtained. The heating temperature is not particularly limited as long as it is sufficient for the polymerization to proceed, but it is generally about 80 to 250 占 폚, preferably about 100 to 200 占 폚, and more preferably about 120 to 170 占 폚. In the case of carrying out the heat polymerization, a polymerization initiator generally used in the composition may be added or may not be added. The thickness of the photo alignment layer formed by the above is preferably about 10 to about 500 nm, more preferably about 100 to about 500 nm, and still more preferably about 100 to about 200 nm.

The retardation film is formed by applying a liquid crystal compound on the photo alignment film obtained above and heating it, irradiating UV light, and heating and baking again.

Examples of the liquid crystalline compound include a polyfunctional liquid crystalline (meth) acrylate having a polymerizable group in the molecule, a liquid crystalline epoxy compound, and a liquid crystalline oxetane compound. Of these, polyfunctional liquid crystalline (meth) acrylates are preferred.

Examples of the polyfunctional liquid crystalline (meth) acrylate include compounds represented by the following formulas (IV) to (VI).

(Formula IV)

Wherein n is an integer of 1 to 18 and R is a hydrogen atom or a methyl group.

(Formula V)

Wherein n is an integer of 1 to 18, R is a hydrogen atom or a methyl group, and Z is a hydrogen atom, a halogen atom or an alkyl group having 1 to 8 carbon atoms.

(VI)

Wherein n is an integer of 1 to 18, R is a hydrogen atom or a methyl group, and Z is a hydrogen atom, a halogen atom or an alkyl group having 1 to 8 carbon atoms.

As the liquid crystalline epoxy compound, for example, a compound represented by the following formula (VII) can be given.

(Formula VII)

(Wherein n represents an integer of 1 to 20, and m represents an integer of 2 to 15.)

The liquid crystalline oxetane compound includes, for example, a compound represented by the following formula (VIII).

(Formula VIII)

Wherein n is an integer of 1 to 18 and Z is a hydrogen atom, a halogen atom or an alkyl group having 1 to 8 carbon atoms.

The temperature at the time of heating after application of the liquid crystalline compound is usually about 50 to 100 占 폚, preferably about 60 to 90 占 폚, and more preferably about 65 to 85 占 폚.

The irradiation with UV light can be carried out in the same manner as the irradiation with the above-mentioned photo alignment film. The heating and baking can be carried out by a usual method. The temperature is usually about 150 to 300 캜, preferably about 200 to 250 캜, and more preferably about 210 to 230 캜. The heating and baking time is about 0.5 to 3 hours, preferably about 0.6 to 2 hours, and most preferably about 0.6 to 1.5 hours.

The film thickness of the retardation film of the present invention thus obtained varies depending on the use and the like. In general, the thickness is preferably in the range of 0.1 to 20.0 mu m, more preferably 1.0 to 5.0 mu m.

In the general formula (I) of the present specification, M1 and M2, which are raw material monomers, are contained in a molar ratio of m: n, and M1 and M2 are not necessarily alternately combined to constitute a copolymer . Therefore, the general formula (1) includes any one of copolymers obtained by polymerizing M1 and M2 in a molar ratio of m: n, for example, alternating type, random type, graft type, and the like. In the general formula (I), the broken line connecting the monomers is usually a single bond. When other monomers are also included in the polymerization of M1 and M2, these monomers may be present in the broken line portion have.

Hereinafter, the present invention will be described in detail with reference to Examples, but the present invention is not limited to the following Examples.

1. Synthesis of copolymer (meth) acrylic acid polymer

[Example 1]

Phenoxyl] hexyloxycarbonyl] -1-methylethylene-CO-1- (2-methoxyphenylsulfonyl) (M1: M2 = 90: 10) (Polymer 1)

5 g (11 mmol) of 4- [6- (2-methylacryloyloxy) hexyloxy] benzoic acid 4 - [(E) -2- methoxycarbonylvinyl] 29.6 g (96 mmol) of methyl acryloyloxy) hexyloxy] benzoic acid and 0.35 g (2.1 mmol) of 2,2'-azobisisobutyronitrile were dissolved in 196 g of cyclohexanone. This solution was ventilated with nitrogen for 1 hour. Then, it was heated at 80 占 폚. After 10 hours, the reaction solution was cooled and added dropwise to 346 g of n-hexane at room temperature with vigorous stirring. The separated polymer was filtered off and dried under reduced pressure at 50 캜 to obtain 26 g of Polymer 1.

≪ Measurement of weight average molecular weight (MW)

The weight average molecular weight (MW) of the polymer obtained above was measured by gel filtration chromatography (GPC). The weight average molecular weight (MW) obtained was 30,700.

≪ Measurement of acid value &

The measurement method is as follows. Approximately 60 ml of THF was taken in a 100 ml Erlenmeyer flask, and phenolphthalein was neutralized with 0.1 mol / l sodium hydroxide aqueous solution as an indicator. Approximately 1.5 g of the polymer was quantitatively weighed and uniformly dissolved in the above solution, stirred, and 0.1 mol / L sodium hydroxide aqueous solution, and the point where the reddish red color did not disappear for about 30 seconds was regarded as the optimum end point.

The acid value was calculated according to the following equation.

Acid value = (0.1 x f x A x 56.1 / B) / (C / 100)

A: Amount (ml)

f: Potency of aqueous solution of sodium hydroxide

B: Amount of polymer composition (g) (amount of solution after completion of titration, including polymer)

C: Polymer concentration (%) (amount of polymer / amount of polymer composition x 100)

The acid value of the polymer obtained above was 156 mgKOH / g.

≪ Measurement of phase transition temperature >

The phase transition temperature of the polymer obtained above was measured using differential scanning calorimetry (DSC) and was 160 to 180 캜.

[Example 2]

Phenoxyl] hexyloxycarbonyl] -1-methylethylene-CO-1- (2-methoxyphenylsulfonyl) (M1: M2 = 80: 20) (Polymer 2) [0154] < EMI ID =

(17 mmol) of 4- [6- (2-methylacryloyloxy) hexyloxy] benzoic acid 4 - [(E) -2- methoxycarbonylvinyl] (69 mmol) of 2-methyl acryloyloxy) hexyloxy] benzoic acid, 0.28 g (1.7 mmol) of 2,2'-azobisisobutyronitrile, and 116 g of cyclohexanone The procedure of Example 1 was repeated to obtain 24 g of Polymer 2.

The obtained polymer had a weight average molecular weight (MW) of 31700, an acid value of 130 mgKOH / g, and a phase transition temperature of 148 to 173 占 폚.

[Example 3]

Phenoxyl] hexyloxycarbonyl] -1-methylethylene-CO-1- (2-methoxyphenylsulfonyl) (M1: M2 = 70: 30) (Polymer 3) [0154] < EMI ID =

(21 mmol) of 4- [6- (2-methylacryloyloxy) hexyloxy] benzoic acid 4 - [(E) -2- methoxycarbonylvinyl] (50 mmol) of 2,2'-azobisisobutyronitrile, 0.23 g (1.4 mmol) of 2,2'-azobisisobutyronitrile, the amount of cyclohexanone used And the amount of n-hexane used was 253 g, to obtain 24 g of polymer 3.

The obtained polymer had a weight average molecular weight (MW) of 33,300 and an acid value of 110 mgKOH / g and a phase transition temperature of 155 to 166 ° C.

[Example 4]

Phenoxyl] hexyloxycarbonyl] -1-methylethylene-CO-1- (2-methoxyphenyl) (M1: M2 = 81: 19) (Polymer 4) [0156] < EMI ID =

2 g (4 mmol) of 4 - [(E) -2-methoxycarbonylvinyl] phenyl ester, 2-fluoro-4- [6 (0.6 mmol) of 2,2'-azobisisobutyronitrile, 116 g of cyclohexanone and 76 g of n-hexane was used as the initiator. Thus, 5 g of polymer 4 was obtained in the same manner as in Example 1.

The obtained polymer had a weight average molecular weight (MW) of 48200, an acid value of 132 mgKOH / g, and a phase transition temperature of 85 to 120 캜.

[Example 5]

Carbonylvinyl] phenoxy] hexyloxycarbonyl] -1-methylethylene-CO-1- [6 (E) -2- (M1: M2 = 80: 20) (Polymer 5)

Cyanophenyl ester (23 mmol), 4- [6- (2-methylacryloyloxy) hexyloxy] - (E) (2.3 mmol) of 2,2'-azobisisobutyronitrile and the used amount of cyclohexanone was changed to 153 g, the procedure of Example 1 was repeated except that 28 g (92 mmol) of benzoic acid was used and the amount of 2,2'-azobisisobutyronitrile was 0.38 g The same treatment was carried out to obtain 22 g of Polymer 5.

The obtained polymer had a weight average molecular weight (MW) of 24,800, an acid value of 135 mgKOH / g, and a phase transition temperature of 160 to 180 캜.

[Comparative Example 1]

(E) -2-hydroxycarbonylvinyl] phenoxy] hexyloxycarbonyl] -1-methylethylene] (Polymer 6)

20 g (23 mmol) of 4- [6- (2-methylacryloyloxy) hexyloxy] - (E) -cinnamic acid was used and the amount of 2,2'-azobisisobutyronitrile was changed to 0.2 g 1.2 mmol), and the amount of cyclohexanone used was 80 g, the procedure of Example 1 was repeated to obtain 17 g of polymer 6.

The obtained polymer had a weight average molecular weight (MW) of 35,000, an acid value of 169 mgKOH / g, and a phase transition temperature of 162 to 197 占 폚.

[Comparative Example 2]

1-methylethylene-CO-1- [6- [4-carboxyphenol] phenoxy] hexyloxycarbonyl] 10 g (30 mmol) of 4- [6- (2-methylacryloyloxy) hexyloxy] - (E) -methylacetic acid, 4- 37 g (120 millimoles) of [6- (2-methylacryloyloxy) hexyloxy] benzoic acid was used, the amount of 2,2'-azobisisobutyronitrile used was 0.5 g (3.0 mmol), cyclohexanone The procedure of Example 1 was repeated, except that the amount of the polymer 7 was changed to 187 g to obtain 40 g of polymer 7.

The obtained polymer had a weight average molecular weight (MW) of 31,000 and an acid value of 178 mgKOH / g and a phase transition temperature of 155 to 182 ° C.

[Example 6]

[(E) -2- [4-methoxyphenoxy] carbonylvinyl] phenoxy] hexyloxylcarbonyl-1-methylethylene-CO-1- [6- [ Methylphenyl] hexyloxycarbonyl] -1-methylethyl] (M1: M2 = 80:20) (Polymer 8)

(23 mmol) of 4- [6- (2-methylacryloyloxy) hexyloxy] - (E) -methoxyphenyl 4-methoxyphenyl ester, 4- [6- (2-methylacryloyloxy ) Hexyloxy] benzoic acid was used, and the amount of 2,2'-azobisisobutyronitrile used was changed to 0.5 g (3 mmol) and the amount of cyclohexanone used was changed to 152 g, 1, 25 g of polymer 8 was obtained.

The obtained polymer had a weight average molecular weight (MW) of 46000, an acid value of 135 mgKOH / g, and a phase transition temperature of 70 to 146 占 폚.

[Example 7]

Poly [1- [6- [4- [4-methoxyphenylazo] phenoxy] hexyloxycarbonyl] -1-methylethylene-CO-1- [6- [4-carboxyphenoxy] hexyloxycar 1- (4-methoxyphenyl) azo] -4- [6- (2-methylacryloyloxy) hexyloxy] (100 mmol) of benzoin and 10.0 g (25 mmol) of 4- [6- (2-methylacryloyloxy) hexyloxy] benzoic acid were used, and the amount of 2,2'-azobisisobutyronitrile (3 mmol) of cyclohexanone, and the amount of cyclohexanone used was 123 g. Thus, 33 g of polymer 9 was obtained.

The obtained polymer had a weight average molecular weight (MW) of 48,000, an acid value of 138 mgKOH / g, and a phase transition temperature of 72 to 148 占 폚.

2. Preparation of composition for photo alignment film

Polymers 1 to 9 were respectively dissolved in cyclohexanone at a concentration of 5% by weight to prepare compositions 1 to 9 for photo alignment layers.

3. Fabrication of photo alignment layer

The composition for photo-alignment film 1 was coated on a glass substrate to a thickness of about 100 nm using a spin coater. Thereafter, it was dried at 80 캜, and then irradiated with linearly polarized UV light at 40 mJ / cm 2. Subsequently, heat treatment was performed at 150 占 폚 for 10 minutes to cause alignment, thereby fabricating a photo-alignment film 1.

The photo alignment layer 2 was prepared in the same manner as in the production of the photo alignment layer 1 except that the amount of linearly polarized UV light irradiation was 30 mJ / cm 2 and the subsequent heat treatment temperature was 140 캜 using Composition 2 for photo alignment layer.

A photo-alignment film 3 was prepared in the same manner as in the production of the photo-alignment film 1 except that the composition for photo-alignment film 3 was used and the irradiation amount of the linearly polarized UV light was 20 mJ / cm 2 and the subsequent heat treatment temperature was 140 캜.

The photo alignment layer 4 was prepared in the same manner as in the production of the photo alignment layer 1 except that the composition for photo alignment layer 4 was irradiated with linearly polarized UV light of 30 mJ / cm 2 and the subsequent heat treatment temperature was 110 캜.

The photo alignment layer 5 was prepared in the same manner as in the production of the photo alignment layer 1 except that the composition for photo alignment layer 5 was used to irradiate linearly polarized UV light at an irradiation dose of 5 mJ / cm 2 and a subsequent heat treatment temperature of 140 캜.

The composition 6 for a photo alignment layer was coated on a glass substrate to a thickness of about 100 nm using a spin coater. Thereafter, it was dried at 120 캜 and then irradiated with linearly polarized UV light at 5 mJ / cm 2. Subsequently, heat treatment was performed at 160 占 폚 for 10 minutes to cause orientation, thereby fabricating a photo-alignment film 6.

The photo alignment layer 7 was prepared in the same manner as the photo alignment layer 6 except that the amount of linearly polarized UV light was 15 mJ / cm 2 and the subsequent heat treatment temperature was 150 캜.

The photo alignment layer 8 was prepared in the same manner as in the production of the photo alignment layer 1 except that the composition for photo alignment layer 8 was irradiated with linearly polarized UV light of 20 mJ / cm 2 and the subsequent heat treatment temperature was 130 캜.

The photo alignment layer 9 was prepared in the same manner as in the production of the photo alignment layer 1 except that the composition for photo alignment layer 9 was irradiated with linearly polarized UV light of 10 mJ / cm 2 and the subsequent heat treatment temperature was 130 캜.

4. Preparation of retardation film

The bifunctional liquid crystalline acrylate represented by the following formula (VI-a)

, A photopolymerization initiator (Irgacure 907, Ciba Specialty Chemicals), 1 wt%, and propylene glycol monomethyl ether acetate (80 wt%).

The composition for the prepared retardation film was coated on the photo alignment film 1 to a thickness of about 2 mu m using a spin coater. Thereafter, the substrate was oriented at 70 캜, and subsequently irradiated with unpolarized UV light at 100 mJ / cm 2. Subsequently, heating and baking were performed at 230 ° C for 1 hour to prepare a retardation film 1.

Thus, retardation films 2 to 9 were formed on the photo alignment films 2 to 9, respectively.

5. Performance evaluation

≪ Solubility of Polymer &

The solubility in 1, 5, 10 and 20% of the polymers 1 to 7 in various solvents was visually evaluated, and the completely dissolved solution was evaluated as? The results are shown in Table 1 (where?,? And? Mean the same in the following table).

The solubilities of 1, 5, 10, and 20% of polymers 8 and 9 in various solvents were visually evaluated. The results are shown in Table 2.

The solubilities of 1, 5, 10, and 20% of the polymers 1 to 9 to 1-methoxy-2-propanol were visually evaluated. The results are shown in Table 3.

≪ Light sensitivity of polymer (polarized light exposure amount) >

For the optimum polarized light exposure and the threshold polarized light exposure of the photo alignment film produced using Polymers 1 to 7, a retardation film was prepared on the prepared photo alignment film, and evaluation was carried out based on the orientation property. Table 4 shows the results of the optimal polarized light exposure amount with the highest orientation and the limiting amount of exposure with which the orientation property starts to decrease.

A retardation film was prepared on the prepared photo alignment film for the optimum polarized light exposure amount and the threshold polarized light exposure amount of the photo alignment film produced using Polymers 8 and 9 and evaluated based on the orientation property. The results are shown in Table 5.

Retention rates of birefringence before and after the firing step were evaluated at the time of manufacturing the retardation film on the photo alignment film produced using Polymers 1 to 7. The birefringence index was measured using a polarization analyzer OPTIPRO (manufactured by Shin-Tek Co., Ltd.) (the same holds true for the subsequent experiments). The results are shown in Table 6.

Retention ratios of birefringence before and after the firing step were evaluated at the time of manufacturing the retardation film on the photo alignment film produced using Polymers 8 and 9.

The results are shown in Table 7.

(Industrial availability)

The copolymerizable (meth) acrylic acid polymer of the present invention is useful as a raw material for a photo alignment film and a retardation film using the same, and the photo alignment film and the retardation film of the present invention are useful as various optical members, particularly OA devices such as computers and facsimiles , A cellular phone, an electronic notebook, a liquid crystal TV, a video camera, and the like.

Claims (4)

In general formula (Ic)

Wherein R ¹ is a hydrogen atom or a methyl group, R ² is an alkyl group, or a phenyl group substituted with a group selected from an alkyl group, an alkoxy group, a cyano group and a halogen atom, and X ^{1 to} X ^{4 A} and X ^{1B to} X ^4B Z is a group represented by -N = N-, p and q are each independently any integer of 1 to 12, and each independently represents a hydrogen atom, an alkyl group, an alkoxy group, a halogen atom or a cyano group, m and n are molar fractions of respective monomers in the copolymer satisfying the relationship of 0.65? m? 0.95, 0.05? n? 0.35, and m + n = 1.
(Meth) acrylic acid polymer having a repeating unit represented by the following general formula
A step of irradiating the film with light having anisotropy, and
A step of heat-treating the film,
And forming a photo-alignment layer on the substrate. The method according to claim 1,
Wherein the temperature of the heat treatment step is a temperature of 120 ° C to 170 ° C. A photo-alignment film produced by the manufacturing method according to claim 1 or 2. A retardation film in which a liquid crystal compound is oriented on the photo alignment film according to claim 3.